Changes in the growth and reproduction of a clonal plant as a result of disruption of mycorrhizal network

In a clonal network, a mother plant is connected with daughter ramets. During network development, new ramets may encounter barriers that disrupt network integrity. As a result, resource allocation within a network is disturbed. In this study, the effect of network integrity disruption on the size of ramets and their sexual reproduction was investigated in mouse-ear hawkweed (Hieracium pilosella). Three types of networks were formed experimentally with unlimited resource allocation, with limited resource allocation between a mother plant and its daughter ramets and with limited resource allocation between all ramets. Networks were either supported by the presence of a mycorrhizal fungus or restricted by its absence. We found that the size of the mother and the effectiveness of sexual reproduction did not differ among network types. The length and dry mass of runners were higher in cases with limited resource exchange between a mother plant and its daughters. In the clonal plant network without any barriers to connection, a higher number of rosettes and lower dry mass of daughters were recorded. The mean number of daughter flowers did not differ among the network types. Mycorrhizal network is one of the most important factors for the sexual reproduction of clonal plants. With a reduced mycorrhizal network, plants invested in clonal growth.

Apomixis and genetic background affect distinct traits in Hieracium pilosella L. grown under competition

Background Apomixis, the asexual reproduction through seeds, occurs in over 40 plant families and avoids the hidden cost of sex. Apomictic plants are thought to have an advantage in sparse populations and when colonizing new areas but may have a disadvantage in changing environments because they propagate via fixed genotypes. In this study, we separated the influences of different genetic backgrounds (potentially reflecting local adaptation) from those of the mode of reproduction, i.e., sexual vs. apomictic, on nine fitness-related traits in Hieracium pilosella L. We aimed to test whether apomixis per se may provide a fitness advantage in different competitive environments in a common garden setting. Results To separate the effects of genetic background from those of reproductive mode, we generated five families of apomictic and sexual full siblings by crossing two paternal with four maternal parents. Under competition, apomictic plants showed reproductive assurance (probability of seeding, fertility), while offspring of sexual plants with the same genetic background had a higher germination rate. Sexual plants grew better (biomass) than apomictic plants in the presence of grass as a competitor but apomictic plants spread further vegetatively (maximum stolon length) when their competitors were sexual plants of the same species. Furthermore, genetic background as represented by the five full-sibling families influenced maximum stolon length, the number of seeds, and total fitness. Under competition with grass, genetic background influenced fecundity, the number of seeds, and germination rate. Conclusions Our results suggest that both the mode of reproduction as well as the genetic background affect the success of H. pilosella in competitive environments. Total fitness, the most relevant trait for adaptation, was only affected by the genetic background. However, we also show for the first time that apomixis per se has effects on fitness-related traits that are not confounded by—and thus independent of—the genetic background.

Pilosella aurantiaca (orange hawkweed).

P. aurantiaca is a perennial herb which has spread rapidly in North America after its introduction as an ornamental and/or the contamination of pasture seeds from its native range in Europe. Although it is known to be a noxious weed elsewhere, it continues to be available as a garden ornamental and is therefore likely to spread further. It is an undesirable invader on account of its competitiveness, prolific seed production and vigorous vegetative growth leading to a drastic change in vegetation, loss in forage for stock, and loss of biodiversity. All Hieracium/Pilosella species are prohibited entry to Australia and New Zealand, and in the USA, P. aurantiaca is a declared weed in Colorado, Idaho, Minnesota and Washington.

Hieracium pilosella L. – a new adventive species for the flora of the Tian Shan (Kazakhstan)

Information is given about the finding of Hieracium pilosella L. in the Issyk River valley on the northern slope of the Zailiysky Alatau ridge. The habitat of the species, the composition of the plant community with its participation are described, the data on the population density of the species, the ratio of generative and vegetative individuals are provided. The appearance of this adventive species in the immediate vicinity of Almaty in the last decade is most likely due to the increasing recreational load on this territory.

The higher units of pine forests of Russia in connection with the general concept of vegetation classification of Northern Eurasia

A review of the classification of pine forests (dominated by two-needle pines of the subgenus Diploxylon) of Russia using the Braun-Blanquet approach was carried out. All diversity of pine forests was included in 9 higher units – vegetation classes, of which 3 classes represent typical communities dominated by pine species (Erico–Pinetea Horvat 1959, Koelerio glaucae–Pinetea sylvestris Ermakov class nova hoc loco, Junipero–Pinetea Rivas-Mart. 1965). In the remaining six classes (Vaccinio–Piceetea Br.-Bl. in Br.-Bl.et al. 1939, Carpino–Fagetea Jakucs et Passarge 1968, Quercetea pubescentis Doing-Kraft ex Scamoni et Passarge 1959, Brachypodio–Betuletea Ermakov et al. 1991, Rhytidio–Laricetea Korotkov et Ermakov 1999 and Quercetea mongolicae Song ex Krestov et al. 2006), pine forests are represented as special higher categories (alliances, orders) along with other types of zonal and non-zonal forest vegetation. The characteristics of the main higher units (classes, orders and alliances) are presented, as well as their diagnostic features and problems of classification of some categories are discussed. As a result of the syntaxonomic revision, the name of the class Pyrolo–Pinetea sylvestris Korneck 1974 was rejected, since the alliance Cytiso–Pinion sylvestris Krausch 1962 (the only alliance of order Pulsatillo–Pinetalia Oberd. in Oberd. et al. 1967) was proposed in the original article as provisional (3b). It is proposed to include xerophilous psammophilous pine forests of Europe and Western Siberia into a new class Koelerio glaucae–Pinetea sylvestris class nova hoc loco. The nomenclature type of the class (holotypus) is the order Koelerio glaucae–Pinetalia sylvestris Ermakov 1999. Diagnostic species of the class are Festuca beckeri, Gypsophylla altissima, G. paniculata, Jurinea cyanoides, Koeleria glauca, Oxytropis campanulata, Potentilla humifusa, Veronica spicata, Silene baschkirorum, S. chlorantha, Stipa pennata subsp. sabuletorum, Helichrysum arenarium, Centaurea arenaria, C. marschalliana, Achillea gebleri, Genista tinctoria, Cytisus ruthenica, C. borystenica, Hieracium pilosella, Dianthus arenarius.

Apomixis and genetic background affect distinct traits in Hieracium pilosella L. grown under competition

BackgroundApomixis, the asexual reproduction through seeds, occurs in over 40 plant families and avoids the hidden cost of sex. Apomictic plants are thought to have an advantage in sparse populations and when colonizing new areas but may have a disadvantage in changing environments because they propagate via fixed genotypes. As a consequence of clonal reproduction, it is very difficult to disentangle the effects of apomictic reproduction from those of genetic background when studying ecological and evolutionary aspects of apomixis.In this study, we separated the influences of different genetic backgrounds (potentially reflecting local adaptation) from those of the mode of reproduction, i.e., sexual vs. apomictic, on nine fitness-related traits in Hieracium pilosella L.. We aimed to test whether apomixis per se may provide a fitness advantage in different competition environments in a common garden setting.ResultsTo separate the effects of genetic background from those of reproductive mode, we generated five families of apomictic and sexual full-siblings by crossing two paternal with four maternal parents. Under competition, apomictic plants showed reproductive assurance (probability of seeding, fertility), while offspring of sexual plants with the same genetic background had a higher germination rate. Sexual plants grew better (biomass) than apomictic plants in the presence of grass as a competitor but apomictic plants spread further vegetatively (maximum stolon length) when their competitors were sexual plants of the same species. Furthermore, genetic background as represented by the five full-sibling families influenced maximum stolon length, the number of seeds, and total fitness. Under competition with grass, genetic background influenced fecundity, the number of seeds, and the germination rate.ConclusionsOur results suggest that both the mode of reproduction as well as the genetic background affect the success of H. pilosella in competitive environments. Total fitness, the most relevant trait for adaptation, was only affected by the genetic background. However, we also show for the first time that apomixis per se has effects on fitness-related traits that are not confounded by - and thus independent of - the genetic background.

Set of additions and changes to Check-list of the flora for the Republic of Buryatia between 2001 to 2020

In preparing the “Keys to Plants of the Republic of Buryatia”, we have searched and systematized the literature sources on vascular plants. From various scientific publications, data on the findings of new plants at the territory of the Republic of Buryatia were extracted and analyzed. The study also found that the published works after the publication of the Key, significantly have changed the idea of the quantitative composition of the flora, which was replenished with 178 species, 1 subspecies and 10 hybrids of vascular plants from 44 families and 131 genera. The largest number of findings was recorded in the families Asteraceae (30 species, 16 genera) and Poaceae (30 species, 20 genera). The most representative genera were Carex, Hieracium, Pilosella, Polygonum.

Dynamics of apomictic and sexual reproduction during primary succession on a glacier forefield in the Swiss Alps

Apomixis, the asexual reproduction through seeds, is thought to provide reproductive assurance when ploidy is not even and/or when population density is low. Therefore, apomicts are expected to be more abundant, and the frequency of apomictic offspring higher, at early stages of primary succession when mates are rare.To test this hypothesis, we sampled facultative apomictic Hieracium pilosella L. along the successional gradient on a glacier forefield and determined their ploidy, the level of apomixis in their offspring, and the genetic diversity of the entire meta-population and within subpopulations.We found that apomixis is more common in odd- and aneuploid cytotypes, which are more frequent at early stages of primary succession. However, apomixis was uncommon at all successional stages and sexual hexaploids were dominating throughout. Reproductive assurance was reflected in the higher fertility of all odd-ploid apomictic plants (3x, 5x) by avoiding meiosis, illustrating that apomixis provides an escape from sterility, as proposed by Darlington. Odd-ploid plants are supposedly better colonizers (Baker’s law), which is supported by their higher occurrence close to the glacier snout. Independent of succession, we found gene flow between apomicts and sexuals, which allows for the continuous creation of new apomictic and sexual genotypes.We conclude that apomixis in H. pilosella does indeed provide an escape from sterility, and therefore reproductive assurance, in aneuploid cytotypes. We further propose that apomixis preserves beneficial combinations of unlinked alleles in every generation for as long as apomictic genotypes persist in the population.